JPH04184957A - Unsealing method of ic package - Google Patents

Abstract

PURPOSE:To enable the title IC package to be unsealed without breaking down the other parts excluding the specific part by a method when a metallic member in different thermal expansion coefficient from that of a ceramic is bonded onto the cap of ceramic package and then the sealed part is broken down by giving thermal shocks. CONSTITUTION:A metallic sheet 6 in different thermal expansion coefficient is stuck on the cap 1 of a ceramic package using a bonding agent 5. Next, the thermal shock is given to the whole package within proper temperature range. Thus, a stress is imposed on the ceramic package due to the difference in the thermal expansion coefficient giving a crack in the most fragile glass sealed part. Furthermore, when the thermal shocks are repeatedly given, the cracked area is spread finally to separate the cap 1 from the ceramic main body 4. Through these procedures, a specimen of the IC package can be unsealed without impressing excessive stress thereon thereby avoiding the mixing of fragments in the IC package or the breakdown of a chip 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for opening an IC package, and particularly to a method for opening a ceramic package using glass as a sealing material. To open the package, use the IC built into the package.
This is done for chip failure analysis, etc.

[Conventional technology]

Conventionally, as a method for opening this type of ceramic package, as shown in FIG.
There is a method of mechanically destroying the gas by pressing the sharp tip 9 of a tool against the gas part 2 that seals the gas. There is also a method in which the entire ceramic package 1.4 is kept at a high temperature higher than the melting point of the sealing glass 2, and the sealing glass is melted and then opened.

[Problem to be solved by the invention]

Among the conventional unsealing methods described above, the mechanical destruction method is extremely simple, but it may cause fragments of the sealed glass or ceramic package to get inside, or in some cases, not only the sealed glass part but also the ceramic package body, There was a drawback that even bonding wires and IC chips were destroyed. Furthermore, the method of melting the sealing glass at a high temperature has the disadvantage that the work must be carried out at a high temperature of approximately 450° C. or higher, and special equipment is required.

Therefore, an object of the present invention is to
To provide a simple method for opening a C package.

[Means to solve the problem]

The present invention is characterized in that a metal member having a coefficient of thermal expansion different from that of ceramic is bonded to the cap of a ceramic package, and the glass sealing portion is destroyed by applying a thermal shock.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a side view showing an embodiment of the present invention, and FIG. 2 is a partially cutaway front view thereof.

As shown in FIGS. 1 and 2, there is a ceramic body 4 housing an IC chip 8 therein, a ceramic cap 1 and a glass sealing part 2 for sealing the body, and an IC chip 8.
is connected to the electrode of the sealing part 2 via the bonding wire 7.
When opening a ceramic IC package consisting of leads 3 led out from a ceramic cap 1, first
A metal plate 6 (for example, an aluminum plate with a thickness of 1 mm) having a coefficient of thermal expansion different from that of the ceramic is pasted onto the ceramic plate using an adhesive 5.

The entire package is then heated to a low temperature (e.g. -30°C to -60°C).
℃) and then placed at a high temperature (e.g. +50℃ to +150℃) (or vice versa) to apply a thermal shock at an appropriate temperature range (e.g. -30℃→+80℃ or 5℃→+130℃). . Then, stress is applied to the ceramic package due to the difference in coefficient of thermal expansion, causing a crack in the weakest glass sealing part, and by repeating the thermal shock, the crack spreads and eventually the ceramic cap 1 separates from the main body 4. . As a specific example, using a commercially available two-bath thermal shock chamber capable of cooling and heating, the entire package was placed in a low temperature chamber for 30 minutes (low m<-55℃), and then moved inside the shock chamber to a high temperature chamber. (moving time is about 20 seconds) and then placing it at a high temperature (+125℃) for 30 minutes for 3 to 5 cycles.
By turning it around, the cap 1 could be easily separated.

〔Effect of the invention〕

As explained above, the present invention is a method of opening a package by creating cracks in the glass sealing part using stress caused by thermal shock, so there is no possibility of debris getting inside the package or of the ceramic package body and IC. This has the effect of preventing chip destruction.

In addition, thermally, there are four
Since there is no need to raise the temperature above 50°C, there is an effect that excessive stress is not applied to the sample, and this is particularly effective for failure analysis and the like.

[Brief explanation of drawings]

FIG. 1 is a side view for explaining the present invention in detail, FIG. 2 is a partially cutaway front view of FIG. 1, and FIG. 3 is a front view showing a conventional method of opening a ceramic IC package. DESCRIPTION OF SYMBOLS 1... Ceramic cap, 2... Glass sealing part, 3... Lead, 4... Ceramic body, 5...
・Adhesive, 6... Metal plate, 7... Bonding wire, 8... IC chip, 9... Sharp tip of tool.

Claims (1)

[Claims] A method for opening a ceramic IC package using glass as a sealing material, characterized in that a metal member having a thermal expansion different from that of the ceramic is adhered to a ceramic cap, and the glass sealing portion is destroyed by applying a thermal shock. How to open an IC package.